1. Field of the Invention
The present invention relates to a semiconductor apparatus, and more particularly, to a fuse box and a method of manufacturing the same.
2. Description of the Related Art
As semiconductor memory devices become more highly integrated and memory capacities thereof increase, the possibility of generating defects in memory cells while manufacturing the semiconductor devices increases, thereby reducing product yields. As a conventional approach to improve the reduction of product yield due to the high integration of semiconductor memory devices, the use of a redundancy circuit is widely used. When a main cell having a defect is detected using a predetermined test, the corresponding fuse in a fuse box is selected and opened so that the defective main cell is substituted with a redundancy cell disposed around the main cell using the redundancy circuit. The fuse is opened using laser blowing. However, in highly integrated semiconductor devices, the fuse size and pitch between fuses are so small that adjacent fuses can be damaged when a fuse is opened in this manner.
FIG. 1 is an image illustrating a defect in which adjacent fuse lines are bridged when a fuse is opened by performing laser blowing, according to conventional art. In a fuse box, a fuse interval in an open region 10a, in which a fuse is opened by laser blowing, is relatively wide, but the fuse interval in an adjacent bundle region 10b, in which a fuse is not opened, is relatively narrow, thereby increasing the density of the fuses. However, when a fuse is opened by laser blowing, the heat that is generated can melt fuses disposed in the adjacent bundle region 10b, and thus the fuses are bridged, as illustrated in a dotted portion of FIG. 1.
To prevent the influence of heat on adjacent fuses when a fuse is opened, a method of forming a capping layer covering the fuses has been suggested.
FIG. 2 is an image illustrating a cross-sectional view of fuse lines 10 on which a capping layer 20 is formed, according to this conventional art approach. The capping layer 20 includes a metal layer 24 and an insulation layer 22. However, the insulation layer 22 in the capping layer 20 and the fuse lines 10, which are formed of metal, can form a capacitor to generate capacitive cross talk. When the capacitive cross talk is generated, a signal can be irregularly transmitted through the fuses, and thus, a defective cell can not be properly substituted with a redundancy cell.